Yes, it possible, but not recommended for the reason already mentioned above.
Maybe it is better if you deposit your USD on an exchange and then start trading on altcoins. When you will earn more that 10$ worth of Bitcoin you will withdraw into your wallet.
Can you deposit $5 on an exchange? Is that enough to start trading with? And don't you need a separate wallet for each altcoin you trade or are those transactions stored on the exchange?
Like I mentioned above...I'm a complete newbie running on information overload. So many questions.